This invention relates to the induction heating of strip and other elongate metal workpieces in which relative movement in the lengthwise direction of the workpiece is effected betweem the workpiece and an induction heater. The invention is applicable to single phase or polyphase induction heaters. The induction heater would normally form part of a fixed heating furnace through which the workpiece is moved.
It is often required to re-heat strip and other elongate metal workpieces, for example before passing them through a rolling mill. It is known to use transversely directed flux for induction heating. The strip is normally but not necessarily moved in a horizontal plane and the poles of the induction heaters are arranged above and/or below the strip so that the flux passes vertically through the strip. The usual practice has been to employ inductors having pole pieces which pole pieces extend transversely across the strip for the whole width thereof. The poles are usually of alternate polarity and may be spaced evenly or unevenly along the length of the strip. One of the problems heretofore has been the non-uniform temperature profile across the width of the strip or workpiece.